Method for cleaning the oral cavity

ABSTRACT

A method for cleaning an oral cavity by positioning a device suitable for detecting and removing plaque from a surface within the oral cavity having applied thereto a fluorescent agent capable of binding to plaque on the surface, substantially simultaneously cleaning and irradiating the surface with a light of a wavelength effective to provide a fluorescent emission when contacted with the fluorescent agent, collecting at least a portion of the fluorescent emission over a predetermined first time period (PTP1), determining an average plaque value (APV) based on the fluorescent emission collected over the PTP1, comparing the APV to a predetermined plaque value (PPV), and continuing to substantially simultaneously clean and irradiate the surface within the oral cavity for a predetermined second time period (PTP2).

FIELD OF THE INVENTION

This invention relates to methods for cleaning surfaces of an oral cavity, e.g. teeth and gums.

BACKGROUND OF THE INVENTION

Biological deposits generally refer to deposits of material of biological origin, such as plaque, bacteria, tartar, and calculus that are generally regarded as undesirable for dental hygiene. Dental plaque is a complex organic deposit generated in part by the activity of bacteria upon surfaces of the oral cavity, such as on the teeth, or upon contamination from, for example, food deposits on the teeth, gums, tongue, or cheek. Plaque is an undesirable precursor to tooth decay and the development of dental caries.

It is desirable to detect plaque deposits in the oral cavity to direct action for removal, for example by using toothbrushes (manual or power), tooth floss, tooth picks, or oral irrigators, as detection indicates the areas at which dental cleaning effort should be focused. Such deposits can be difficult to detect in situ/in vivo on the teeth, gums, tongue, or cheek. It is especially important to detect dental plaque. For detection of plaque it is known to use fluorescence measurement, in which incident radiation is directed at the surfaces of the oral cavity, and fluorescence radiation having characteristics associated with the presence of biological deposits is emitted from the surfaces and is detected.

In the state of the art there are two general methods for detecting dental plaque. One method uses primary fluorescence, where the fluorescence of dental plaque or other dental material itself is monitored. The other method uses secondary fluorescence, where surfaces in the oral cavity suspected of bearing plaque are treated with a fluorescent label material which preferentially binds to dental plaque, and the fluorescence emission of the label material on the oral cavity surfaces to which it has bound is detected to indicate the presence of dental plaque. Also known are toothbrush heads having a bundle of optical fibers extending through it to direct incident radiation at a test tooth surface, and to collect emitted radiation from the test tooth surface.

A requirement of such methods is that incident radiation is directed at the surfaces of the oral cavity under examination and that consequent fluorescence emission radiation from those surfaces is collected. The amplitude of that radiation is a function of the amount of biological deposit located on the surface, as well as the distance the light source and detectors are from the surface. Consequently, the actual plaque value detected will fluctuate depending upon such factors, thereby resulting in a plaque value which may not truly depict the condition of plaque on the surface of the oral cavity. Known devices are not known to compensate for distances between the source of radiation and/or sensors and the surface of the oral cavity when determining the amount of biological deposit on the oral cavity surfaces.

Devices and methods for detecting and removing plaque in the oral cavity according to the invention described and claimed herein provide improved methods of cleaning teeth, particularly where plaque is detected and removed.

SUMMARY OF THE INVENTION

The present invention is a method for cleaning an oral cavity. The method includes the steps of positioning within the oral cavity a device suitable for detecting and removing plaque from the surface of the oral cavity, where the device includes a source for emitting light. The surface of at least one tooth in the oral cavity has applied thereto a fluorescent agent capable of binding to plaque on the at least one tooth. The surface is substantially simultaneously cleaned and irradiated with a light of a wavelength effective to provide a fluorescent emission when contacted with the fluorescent agent on the at least one tooth. At least a portion of the fluorescent emission is collecting over a predetermined first time period. An average plaque value is determined based on the fluorescent emission collected over the predetermined first time period and compared to a predetermined plaque value. The at least one tooth is substantially simultaneously cleaned and irradiated for a predetermined second time period. A range of the distance of the light source from the surface is determined over the predetermined second time period and the distance range is compared to a predetermined distance threshold. Simultaneous cleaning and irradiation of the surfaces of the oral cavity is continued until all of a plurality of sections in the oral cavity has been cleaned, or for a predetermined maximum time period, whichever occurs first.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the operating principle of the cleaning device and methods of the present invention.

FIG. 2 shows a top plan view of an embodiment of the bristle face of a toothbrush head embodiment useful in the present invention.

FIG. 3 illustrates an embodiment method of the present invention.

FIG. 4 is a sample plot of data produced from prototype oral cleaning device during a 10 second brushing of a particular segment of the mouth.

FIG. 5 is a cross-sectional view of an embodiment of a device for use in cleaning surfaces of the oral cavity according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following terms are used interchangeably both in the specification and the claims. APV is used interchangeably with average plaque value. ACPV is used interchangeably with average compensated plaque value. PMTP is used interchangeably with predetermined maximum time period. PTP is used interchangeably with predetermined time period. PPV is used interchangeably with predetermined plaque value. PDT is used interchangeably with predetermined distance threshold.

A device and methods for cleaning a surface of the oral cavity are provided, including detecting and removing plaque on the surface of the oral cavity, e.g. teeth and gums. The device comprises a radiation source for directing incident radiation onto a surface within the oral cavity to which a fluorescent agent has been bound. The device further comprises a means to clean the surface of the oral cavity. Once having the benefit of this disclosure, one skilled in the art will recognize that there are multiple embodiments suitable to clean the surface of the oral cavity, e.g. teeth. For example, toothbrushes, whether power drive or manual, are useful in the present invention. Furthermore, such devices that provide pressurized water to clean the dental and interdental surfaces may be used in the present invention. Additionally, means for providing sonification in a water stream applied to the surface of the oral cavity may be used in the present invention.

“Fluorescent agent”, as used herein, means a composition or compound applied to the surface of the oral cavity, e.g. teeth or gums, which is capable of binding to plaque present on the surface in the oral cavity and is capable of providing a fluorescent emission when irradiated with incident radiation of a particular wavelength. By “binding” or “bound” to plaque, it is meant that the fluorescent agent is attached to plaque deposits on the surface of the oral cavity such that it will not be separated from the plaque deposit under conditions of cleaning as described herein. For example, brushing of the treated surface with a toothbrush, either manual or power, will not result in the fluorescent agent being removed from the surface unless the plaque to which it is attached is removed from the surface.

The radiation source typically may provide light having a peak wavelength of from about 450 to about 500 nanometers, although the range may vary depending upon the particular fluorescent agent applied to the surface of the oral cavity to be cleaned. The device may optionally include a filter for filtering incident radiation prior to contact with the surface of the oral cavity to be examined. The device also includes optical collectors for collecting fluorescent emission, and optionally reflected light, resulting from contact of the incident radiation with the treated surface. In certain embodiments, the optical collectors may comprise optical fibers or filaments. The device also includes an optical pathway for conveying the collected fluorescent emission and reflected light in the device. In certain embodiments, the optical pathway may comprise optical fibers. As such, optical fibers may serve both to collect and convey the reflected light and fluorescent emission.

The device further includes electrical components for sensing, or detecting, the optical light of the fluorescent emission, means for converting the optical light signal to an electrical signal and a data processor for manipulating the electrical signal correlating to the collected fluorescent emission taken over iterative intervals so as to determine an average plaque value. As such, plaque value, as discussed and determined herein, is based upon and correlates to the fluorescent emission generated by contact of the incident radiation with the fluorescent agent and collected by the device.

In embodiments where both reflected light and fluorescent emission are collected, the device further includes electrical components for sensing the optical light signal of the reflective light and the fluorescent emission. In one embodiment, the optical light signals of the reflective light and the fluorescent emission are sensed, or detected, sequentially, but essentially simultaneously. By essentially simultaneously, it is meant that, while measurements are not taken exactly at the same time, the difference in time between detecting the reflective light and fluorescent light, respectively, is so small that the detection of each approximates the simultaneous reading. The device further comprises means for converting an optical light signal to an electrical signal, for example, a transducer. The devices may include means for amplifying or conditioning the electrical signal, thus providing a smoother or averaged signal, or a signal with reduced noise. The device also includes a data processor which may contain an analogue-to-digital converter for converting the electrical signal from an analogue format to a digital format. The processor then mathematically manipulates the electrical signal of the collected reflected light and fluorescent emission taken over iterative intervals so as to determine an average compensated plaque value (ACPV) over a particular time period. By “compensated plaque value”, it is meant that the plaque value is determined taking into account the distance between the optical collector and the surface of the oral cavity being examined. As such, the compensated plaque value is determined as a function of the distance between the optical collector and the surface of the oral cavity at any given moment/reading. As a result of determining plaque value as a function of distance, the compensated plaque value so determined will be substantially the same for a particular surface at any particular moment/reading, irregardless of the actual distance between the radiation source and the surface of the oral cavity being cleaned. By substantially the same, it is meant that the determined compensated plaque value at any given distance will be statistically the same. The device may be used as a component of, or in combination with, oral cleaning devices such as toothbrushes, whether manual or power.

Methods and devices of the present invention for cleaning surfaces in the oral cavity, e.g. teeth and gums, involve the use of a fluorescent agent applied to the surface in the oral cavity prior to cleaning. For example, fluorescein or salts thereof, e.g. sodium fluorescein, are known fluorescent agents and may be dispersed in a suitable medium, such as toothpaste, a dental gel, or a rinse containing the fluorescent agent. The fluorescent agent can be applied either by first rinsing the oral cavity with the fluorescent agent or by applying the toothpaste or dental gel containing the fluorescent agent. The plaque on the surfaces of the oral cavity retains an amount of fluorescent agent that is proportionate to the amount of plaque on the surface. While fluorescein is one example of a fluorescent agent, other agents are known that will bind to plaque similar to fluorescein. The particular wavelength of the incident radiation used in methods and devices of the present invention will vary, depending on the particular fluorescent agent chosen.

After application of the fluorescent agent to the surface in the oral cavity to be cleaned, the user positions the device that is suitable for detecting and removing plaque from the surface of the oral cavity within the oral cavity and proceeds to clean the surface. The oral cavity may be partitioned into a plurality of sections, for example, from 4 to 16 sections, so that cleaning of the oral cavity can take place in stages, proceeding from one section to another until the entire surface in the oral cavity, e.g. teeth and/or gums, is cleaned. The number of sections into which the oral cavity is partitioned may be pre-selected and programmed into the device, as described herein below. Alternately, the number of sections may be determined on a continuous basis during cleaning, based on readings of average fluorescent emission being taken continuously throughout the cleaning process. In either case, the device itself provides a prompt to the user, for example, without limitation, auditory, visual, or vibratory, indicating that the user should move the device to another of the plurality of sections in the oral cavity.

In practice, the device is positioned within one of the plurality of sections of the oral cavity to be cleaned. The device substantially simultaneously cleans, or brushes in the case of a toothbrush having bristles, and irradiates a surface of at least one tooth in the section of the oral cavity being cleaned with incident radiation. The surface of the tooth in the section being brushed and irradiated has applied thereto a fluorescent agent capable of binding to plaque on the surface of the at least one tooth. The surface is irradiated with incident radiation of a wavelength effective to provide a fluorescent emission when contacted with the fluorescent agent bound to the plaque on the surface of at least one tooth.

The method of the invention includes collecting at least a portion of the fluorescent emission from the surface being cleaned over a predetermined first time period (PTP1) and then determining an average plaque value (APV). The APV is the average plaque value based on multiple fluorescent emission readings collected over the PTP1. The APV is then compared to at least one predetermined plaque value (PPV1). The user continues to substantially simultaneously brush and irradiate the at least one tooth in the section for a predetermined second time period (PTP2). The duration of the PTP2 will be determined by the comparison of the APV to the PPV, with the duration being longer for areas with a greater APV, as described in more detail herein below. For example, if the APV is greater than the PPV1, the PTP2 for continued brushing will be set to one value. If the APV is less than the PPV1, the APV is compared to a second predetermined plaque value (PPV2), which is less than the PPV1. If the APV is less than the PPV1 but greater than the PPV2, the PTP2 based upon the PPV2 will be less than what it would be for PPV1. If the APV is less than the PPV2, the APV is compared to a third PPV3, which is less than the PPV2, and the PTP2 based upon PPV3 will be less than it would be for PPV2.

Substantially simultaneously with cleaning and determining the APV over the respective PTP, the distance between the radiation source and the surface being cleaned may be recorded by the device. Multiple readings of distance may be taken over a particular PPT. The range of distance readings taken over the respective PTP then may be compared to a predetermined distance threshold (PDT) to ensure that the cleaning device has been maintained within a distance from the surface being cleaned to provide effective cleaning of the surface. Those skilled in the art will realize that the distance readings, per se, while being based upon the level, or intensity, of the fluorescent emission and reflected light collected, are recorded as electrical signals, e.g. voltage, etc., with the greater the signal indicating that the device is closer to the surface, and the lower the signal indicating that the device is farther away. For example, on a scale of 0-10, 10 would indicate that the device is in close proximity with the surface, while 0 would indicate that the device has been moved too far away from the surface to effectively clean same. If the PDT were established as 5, for example, distance values greater than or equal to the PDT would be preferred, while values below 5 would be less preferred. The distance readings and the PDT thus are values that are based upon the respective fluorescent emission and reflected light and result from processing of same. Distance values greater than the PDT indicate that the cleaning device is positioned appropriately within the oral cavity with respect to the surface being cleaned.

If the APV is greater than the particular PPV to which it is being compared, and all distances within the range measured over the PPT are greater than or equal to the PDT, the user is prompted by the device to move the device to a different section. If any of the recorded distance readings are less than the PDT, the device is maintained within the section currently being cleaned. In either case, cleaning continues and the cycle is repeated until the total cleaning time has exceeded a predetermined maximum time period for the oral cavity, at which time the device indicates to the user that the cleaning process has been completed in the oral cavity, or until all sections of the oral cavity have been cleaned, whichever occurs first.

In certain embodiments, reflected light resulting from contact of the incident radiation with the treated surface is collected essentially simultaneously with the fluorescent emission. In these embodiments, the fluorescent emission values are compensated fluorescent emission values, as defined herein above.

FIG. 1 is a schematic diagram of the operating principle of methods and devices for cleaning surfaces of the oral cavity according to the present invention. The particular embodiment represented is a toothbrush, although other devices for use within the oral cavity also are contemplated by the invention. FIG. 2 is a plan view of a toothbrush head according to the invention, taken from the bristle side of the brush head. In the embodiment shown, toothbrush head portion 14, represented as a first dashed box on FIG. 1, includes, in addition to conventional bristle tufts 26 for cleaning teeth, radiation source 22 and optical fibers 24 a and 24 b for conveying reflected light 33 and fluorescent emission 34 resulting from contact of the surface of the oral cavity with the incident radiation. Head 14 also may include first optical filter 42, depending on the radiation source.

Electrical housing 18, represented as a second dashed box in FIG. 1, will contain other electrical components of a plaque detecting device located therein, as described herein above. In some embodiments, electrical housing 18 may reside in a handle portion of the cleaning device, for example a toothbrush handle. In the embodiment shown, optical fibers 24 a and 24 b extend from head 14 into electrical housing 18. Housing 18 also includes contained therein, second optical filter 44, first optical transducer 46, second optical transducer 48, first amplifier 52, second amplifier 54, data processor 56 and power source 50 for operating the electrical components.

FIG. 1 also shows a representative surface of the oral cavity, e.g. tooth 60, with top surface 62 and side surface 64. Though FIG. 1 shows device 10 directed at top surface 62 of tooth 60, it is to be understood that both top surface 62 and side surface 64 of tooth 60, may be contacted with incident radiation. In addition, such contact may be simultaneously at top surface 62 and side surface 64 of multiple teeth 60, depending on the brushing technique of the user. The cleaning device may also be directed at other surfaces in the oral cavity, such as those of the gums, tongue, or cheek.

In operation, prior to use of the cleaning device, the oral cavity is treated with a fluorescent label material, i.e. a fluorescent agent, which preferentially binds to dental plaque and which produces a fluorescent emission when exposed to incident radiation. Depending on the particular fluorescent agent chosen, the peak wavelength of the incident radiation may vary. In embodiments utilizing fluorescein or salts thereof, e.g. sodium fluorescein, the incident radiation may have a peak wavelength ranging from about 450 to about 500 nanometers. Once placed within the oral cavity, radiation source 22 emits light at a peak wavelength of from about 450 to about 500 nanometers (nm), or about 470 nanometers. The light may be passed through first optical filter 42, which removes substantially all light having wavelength above about 510 nm. As shown, incident radiation 32 from radiation source 22 is directed at top surface 62 of tooth 60, although as discussed above, the incident radiation may contact multiple surfaces of the oral cavity, e.g. the teeth. Upon contact with the surface, incident radiation interacts with the fluorescent agent that has bonded to plaque located on the surfaces of tooth 60. The fluorescent agent then produces a fluorescent emission 34 having a peak wavelength of from about 520 to about 530 nanometers. A first portion of fluorescent emission 34 provided by the fluorescent agent is collected by optical fibers 24 a and conveyed in the device by optical fibers 24 a for further mathematical processing. Incidentally, a second portion of reflected light 33 is essentially simultaneously collected and conveyed with the first portion of fluorescent emission 34. Fluorescent emission 34 is passed through a second optical filter 44, which removes substantially all light of wavelengths below about 515 nm, ensuring that essentially no reflected light is passed to the data processor 56. The now filtered fluorescent emission 34 passes through first optical transducer 46 in the form of a photodiode, which converts the optical light signal into an electrical signal. The electrical signal is passed through first amplifier 52 to increase the electrical signal being passed to data processor 56.

A first portion of the reflected light is collected by optical fibers 24 b and conveyed in the device by optical fibers 24 b for further mathematical processing. Incidentally, a second portion of fluorescent emission 34 is collected and conveyed with the first portion of reflected light. The second portion of fluorescent emission 34 and the first portion of the reflected light are conveyed through second optical transducer 48, in the form of a photodiode, which converts the optical light signal into an electrical signal. While it is an option to provide an optical filter to remove substantially all of the fluorescent emission prior to passing through second optical transducer 48, in the embodiment shown, neither the second portion of the fluorescent emission, nor the first portion of reflected light is filtered prior to their passing through second optical transducer 48, as these signals are used to measure the distance from the radiation source 22 to the surface of tooth 60. The unfiltered electrical signal is passed through second amplifier 54 to increase the electrical signal being passed to data processor 56.

Electronic parts that may be used in plaque detecting device 10 may include Taos TSL12S-LF photodiodes, Opamp Analog AD8544ARZ amplifiers, Semrock fluorescence filters (FF01-500-LP, FF01-475/64), and Atmel ATMEGA8L-8AU microprocessor.

Data processor 56 performs a mathematical manipulation on the inputs from first optical transducer 46 and second optical transducer 48. In the mathematical manipulation, the electrical signal resulting from filtered fluorescent emission 34 is modified to account for the electrical signal received from the unfiltered electrical signal that was used to determine distance from the tip of optical fiber 24 b, i.e. the optical collector, to the surface of tooth 60. The relationship between the two signals is experimentally determined by measuring their respective signal strengths at known distances from the surface of objects coated with a fluorescent agent. The result of the mathematical manipulation is a corrected electrical signal which results in a compensated plaque value, as that term is described and defined herein.

FIG. 2 shows a plan view of a first embodiment of a device of the present invention. As shown, device 10 is in the form of a toothbrush with a handle portion 12 and a head portion 14. FIG. 2 shows the bristle face 16 of device 10. Bristle face 16 of head portion 14 is shown as generally oval in shape, but it is important that bristle face 16 may be in shapes such as triangle, square, rectangle, trapezoid, and other polygons, or circle, ellipse, crescent, deltoid, asteroid, or other curved shapes.

Radiation source 22, optical collectors and conveyors 24 and cleaning tufts 26 are located on bristle face 16. Radiation source 22, preferably in the form of a light emitter such as a light-emitting diode (LED), directs incident excitation radiation at the surfaces of the teeth to be cleaned. Optical collectors and conveyors 24, typically in the form of optical fibers, collect the fluorescent radiation emitted from the teeth. The optical fibers may be made of glasses such as silica, but may be made of other materials, such as fluorozirconate, fluoroaluminate, and chalcogenide glasses, but may also be in the form of plastic optical fibers (POFs).

Cleaning tufts 26 are made of approximately 20 to 50 individual bristles arranged on bristle face 16 in a manner to optimize cleaning of the surfaces of the teeth. FIG. 1 shows one arrangement of tufts 26 on bristle face 16. It is to be understood that the arrangement of tufts 26 on bristle face 16 is not limiting in the scope of the present invention. Typical tufts are approximately 0.063 inches (1.6 mm) in diameter, with a cross-sectional area of approximately 0.079 inches² (2 mm²). The diameters of commonly used bristles are: 0.006 inch (0.15 mm) for soft bristles, 0.008 inch (0.2 mm) for medium bristles, and 0.010 inch (0.25 mm) for hard bristles.

A general problem in the recognition of caries, plaque or bacterial infection on teeth with the above-described method is found in that the detected fluorescent radiation can be disruptively superimposed with daylight or the artificial room lighting. This environmental light can likewise be reflected from the tooth 60 and thus collected by optical fibers 24 a and 24 b. The spectral region of the environmental light lying in the detection region in accordance with the invention results in a background signal, i.e. noise, which restricts the sensitivity of plaque detection.

This problem is effectively resolved in accordance with the invention in that the incident radiation 32 generated by radiation source 22 is periodically modulated. In this case, because of the short duration of the excited state the fluorescent emission 34 follows the intensity of the excitation radiation practically instantaneously. In contrast, the environmental light is not periodically modulated and is superimposed on the detected emission 34 solely as a constant component. For evaluation of the emission 34, now only the radiation modulated with the corresponding frequency is employed as detection signal and evaluated. In this way, the constant component of the environmental light is quasi-filtered out and plaque is detected virtually independently of the environmental light. Since the environmental light is, however, modulated slightly with the frequency of the mains voltage, there should be chosen as modulation frequency for the incident radiation 32 at a frequency which differs distinctively from the mains voltage frequency and preferably lies in the range between 100 Hz and 200 kHz.

The devices and methods for detecting and removing plaque in the oral cavity may also be used as part of, or in combination with, oral care systems which track the health of the oral cavity. Such systems can record plaque levels on teeth, gum, tongue, or cheek surfaces, before and after cleaning operations, as well as the track the plaque of levels over time, reporting the results to the user, or to dental care professionals.

There are a numbers of different methods, or modes, of using the oral cleaning device of the present invention in detecting and removing plaque in the oral cavity. For illustrative purposes, and not meant to be limiting in scope, reference is made to FIG. 1. FIG. 3 illustrates one embodiment method of use of the oral cleaning device 10 of the present invention. In this embodiment, the user is instructed to divide the teeth cleaning operation into a number, i.e. a plurality, of sections within the oral cavity, and to move from section to section upon receiving an OUTPUT SIGNAL from oral cleaning device 10. The order in with the sections are cleaned is not critical to the performance of oral cleaning device 10. The number of sections can be 16, 12, 10, 8, 6, or 4.

In the first step, oral cleaning device 10 is turned on, and a GLOBAL TIMER, which counts up from time 0 to a predetermined maximum end time for cleaning the oral cavity, and a LOCAL TIMER, which counts down from a predetermined time to time 0 in a particular section, are set to zero. Progressing to the next step, incident radiation from radiation source 22 is directed at top surface 62 or side surface 64 of a tooth 60 (or teeth) in the section being cleaned. Processor 56 waits until the strength from the unfiltered electrical signal that was used to determine distance from the radiation source 22 to the surface of tooth 60 is above a preset DISTANCE THRESHOLD1. This is to insure that radiation source 22 is positioned within close proximity to the top surface 62 or side surface 64 of tooth 60. When the strength from the unfiltered electrical signal is above the preset DISTANCE THRESHOLD1, the program progresses to the next steps, the COUNTER is set to 0, and the GLOBAL TIMER is started.

Progressing to the next step, processor 56 initiates the algorithm on the inputs from first optical transducer 46 and second optical transducer 48, resulting in a corrected electrical signal. LOCAL TIMER is set to a predetermined INITIAL TIME. An average plaque value is calculated from INITIAL TIME to time 0, i.e. a first time period, and recorded as PLAQUE. The INITIAL TIME and thus the first time period could be values such as, but not limited to, 10, 5, 4, 2, 1, 0.5, or 0.25 seconds. The average plaque value may, in some embodiments, be calculated by taking data at intervals such as 1, 0.5, 0.25, 0.125, 0.1, 0.05 0.025, 0.0125, 0.01, or 0.005 seconds over the first time period, and averaging the corrected electrical signal values over the number of data points measured. The time intervals for data recording may be regular, or can be randomly chosen over the first time period.

The operating program in processor 56 now reaches a first decision block. In this block, the APV is compared to a first preset plaque value (PPV1). PPV1 may be experimentally determined as an average value in a chosen population of users of oral cleaning device 10, or may be determined for the specific user of device 10.

If the value of APV is greater than the PPV1, the operating program in processor 56 sets LOCAL TIMER to BRUSH TIME1 (BT1). BT1 may be experimentally determined as an average cleaning time for a chosen population of users of oral cleaning device 10 to clean their teeth when APV is greater than the PPV1, or may be determined for the specific user of device 10. During this BT1, the unfiltered electrical signal that is used to determine distance from the radiation source 22 to the surface of tooth 60 is stored as DISTANCE RANGE. This is a measure of the distance of radiation source 22 to the top surface 62 or side surface 64 of tooth 60. DISTANCE RANGE values may, in some embodiments, be calculated by taking data at intervals such as 1, 0.5, 0.25, 0.125, 0.1, 0.05, 0.025, 0.0125, 0.01, or 0.005 seconds.

If the value of APV is not greater than the PPV1, the operating program in processor 56 progresses to a second decision block. In this block, the APV is compared to a second preset plaque value (PPV2). PPV2 is less than PPV1, and like PPV1, PPV2 may be experimentally determined as an average value in a chosen population of users of oral cleaning device 10, or may be determined for the specific user of device 10.

If the APV is greater than the PPV2, the operating program in processor 56 sets LOCAL TIMER to BRUSH TIME2 (BT2). BT2 may be experimentally determined as an average cleaning time for a chosen population of users of oral cleaning device 10 to clean their teeth when APV is greater than the PPV2, or may be determined for the specific user of device 10. During this time period, the unfiltered electrical signal that is used to determine distance from the radiation source 22 to the surface of tooth 60 is stored as DISTANCE RANGE.

If the APV is not greater than the PPV2, the operating program in processor 56 progresses to a third decision block. In this block, the APV is compared to a third preset plaque value (PPV3). PPV3 is less than PPPV2, and like PPV1 and PPV2, PPV3 may be experimentally determined as an average value in a chosen population of users of oral cleaning device 10, or may be determined for the specific user of device 10.

If the value of APV is greater than the PPV3, the operating program in processor 56 sets LOCAL TIMER to BRUSH TIME3 (BT3). BT3 may be experimentally determined as an average cleaning time for a chosen population of users of oral cleaning device 10 to clean their teeth when APV is greater than the PPV3, or may be determined for the specific user of device 10. During this time period, the unfiltered electrical signal that is used to determine distance from the radiation source 22 to the surface of tooth 60 is stored as DISTANCE RANGE.

FIG. 3 shows fourth and fifth decision blocks, with preset values of plaque (PPV4 and PPV5). The PPV5 is less than the PPV4, which in turn is less than the value of PPV3. Correspondingly, the value of BT1>BT2>BT3>BT4>BT5, reflecting the concept that higher values of APV require longer times for plaque removal.

It is important to note that, although this example uses PPV1, PPV2, PPV3, PPV4, and PPV5, corresponding to BT1, BT2, BT3, BT4, and BT5, the operating program in processor 56 can use more or less than 5 preset plaque values to compare to the PPV when determining how long of a brushing time is needed. BT1, BT2, BT3, BT4, and BT5 may have values such as 45, 30, 15, 10, 7.5, 5, 4, 3, 2, 1, or 0.5 seconds, and may be determined by routine experimentation with oral cleaning device 10.

If the APV is not greater than the PPV5, the operating program in processor 56 progresses to a final block. In this block, if the value in the GLOBAL TIMER is greater than the predetermined maximum time period for cleaning the oral cavity, the operating program in processor 56 has an END signal sent to the user to inform the user that the cleaning process is complete. If not, an OUTPUT SIGNAL is sent to the user to inform the user to move to a new section of the mouth every 30 seconds (optionally 20, 15, 10, or 5 seconds) until the GLOBAL TIMER is greater than the predetermined maximum overall cleaning time, at which point the operating program in processor 56 has an END signal sent to the user to inform the user that the cleaning process is complete. The predetermined maximum overall cleaning time in the embodiment shown in FIG. 3 is 120 seconds (2 minutes), but could be 120, 150, or 180 seconds.

If the APV was greater than any of PPV1 through PPV5, LOCAL TIMER will count down to 0. Now, the operating program in processor 56 moves to the sixth decision block. In this block, the value of DISTANCE RANGE is compared to preset minimum DISTANCE THRESHOLD2. If any of the distance values within the DISTANCE RANGE are less than minimum DISTANCE THRESHOLD2, which is an indication that the user moved radiation source 22 out of the cleaning range for top surface 62 or side surface 64 of tooth 60, than the operating program in processor 56 moves to a block that resets the LOCAL TIMER and the device is maintained within the section being cleaned.

If none of the values within the DISTANCE RANGE are less than DISTANCE THRESHOLD2, than the operating program in processor 56 moves to a block that has an OUTPUT SIGNAL sent to the user to inform the user to move the oral cleaning device 10 to the next section for cleaning. The operating program in processor 56 progresses to the next step, where the value of COUNTER is increased to COUNTER+1.

The operating program in processor 56 progresses to the next step, where the LOCAL TIMER is reset, and the program in processor 56 progresses to the seventh decision block. In this decision block, the value of COUNTER is compared to a preset COUNTER MAX1. If the value of COUNTER is less than preset COUNTER MAX1, the program in processor 56 progresses to the eighth decision block.

In the eighth decision block, the value of the running time in the GLOBAL TIMER is compared to a predetermined GLOBAL MAX. If the value of the running time in the GLOBAL TIMER is less than the predetermined GLOBAL MAX, the operating program in processor 56 proceeds to the next step, where processor 56 waits until the strength from the unfiltered electrical signal that was used to determine distance from the radiation source 22 to the surface of tooth 60 is above a preset DISTANCE THRESHOLD1, and returns to the block that calculates a new APV.

If the value of the running time in the GLOBAL TIMER is greater than the predetermined GLOBAL MAX, the operating program in processor 56 proceeds to the next step, and the END signal is sent to the user to inform the user that the cleaning process is complete. As mentioned above, the END signal sent to the user to inform the user that the cleaning process is complete, as well as the OUTPUT SIGNAL sent to the user to inform the user to move the oral cleaning device 10 to the next section for cleaning, may be in a number of forms. These signals may be in forms directed to any of the five senses: sight, sound, touch, smell, or taste.

If, in the seventh decision block, the value of COUNTER is not less than preset COUNTER MAX1, the program in processor 56 progresses to the ninth decision block. In this decision block, the value of the running time in the GLOBAL TIMER is greater than a predetermined GLOBAL MIN, the operating program in processor 56 proceeds to the next step, and the END signal is sent to the user to inform the user that the cleaning process is complete.

If the value of the running time in the GLOBAL TIMER is less than the predetermined GLOBAL MIN, the operating program in processor 56 proceeds to the next step, where processor 56 waits until the strength from the unfiltered electrical signal that was used to determine distance from the radiation source 22 to the surface of tooth 60 is above a preset DISTANCE THRESHOLD1, and returns to the block that calculates a new value for PLAQUE.

FIG. 5 is a cross-sectional view of an embodiment of a device 100 for use in cleaning surfaces of the oral cavity according to the present invention. The particular embodiment represented is a toothbrush, although other devices for use within the oral cavity also are contemplated by the invention. As shown in FIG. 5, device 100 has a handle portion 102, a neck portion 104, and a toothbrush head portion 114. Toothbrush head portion 114 includes bristle tufts 126 for cleaning teeth and radiation source 122. Handle portion 102 is hollow, and optical transducers 146 and 148, amplifiers 152 and 154, data processor 156 and power source 150 are contained therein.

The present invention may be better understood with reference to the following examples.

EXAMPLES Example 1 Determination of the Compensated Plaque Value

A plaque detecting toothbrush was created by modifying the head of a manual toothbrush by inserting a blue light-emitting diode (LED) facing outwards from the head, allowing the light from the LED to illuminate the tooth surface. The LED was surrounded by an array of 12 fiber optic filaments, also pointed towards the tooth surface in the area illuminated by the blue LED. The fiber optics passed through the neck of the toothbrush to a pair of photo sensors (Taos TSL12S-LF) contained in the handle section of the toothbrush. The fibers were separated into two groups. One group passed through an optical filter (Semrock FF01-500/LP) that allowed only wavelengths above 515 nm to pass, while the second group allowed all wavelengths to pass, i.e. no optical filter was utilized. The filtered light represented the plaque value while the unfiltered light was used to interpret the distance between the optical collector, i.e. the tips of the optical fibers, and the surface of the tooth. The output of the photo sensors were connected to amplifiers (Analog devices AD8544ARZ) which in turn were connected to an 8 bit microcontroller (Atmel ATMEGA8L-8AU). The microcontroller contained two 10 bit analog to digital converters that allowed the information to be manipulated in a digital format within the microcontroller.

Using this apparatus, experiments were performed by using Typodent teeth models coated with a simulated plaque material containing a fluorescent material. The artificial plaque was painted onto the tooth surfaces in a way that approximated the manner in which plaque grows in the human mouth. The experiments consisted of positioning the optical collectors, e.g. the tips of fiber optic filaments, at varied distances from the tooth surface so as to enable a relationship to be created between the distance and the plaque value.

The prototype device was operated with the following set of parameters:

-   -   Sampling at 500 Hz (0.002 seconds), sequentially taking 4         measurements in repeating succession.     -   Averaging every 20 data points per output data value.     -   Device powered by 8-bit microcontroller at 7 MHz clock speed.     -   RS232 readout of data to a spreadsheet, and     -   Ambient light compensation.

The device was placed at distances between 0 and 10 mm from the surface of the model tooth surface. Readings were taken with Distance LED on, Distance LED off, Plaque LED on, and Plaque LED off. The value of the signals for Total Plaque and Total Distance were calculated at each distance using:

Total Plaque=Plaque LED on−Plaque LED off  (I)

Total Distance=Distance LED on−Distance LED off.  (II)

Table I shows the measured/calculated values for Plaque LED on, Plaque LED off, Total Plaque, Distance LED on, Distance LED off, Total Distance.

TABLE I Distance and Plaque readings from prototype oral cleaning device. Dis- Plaque Plaque Total Total tance LED LED Plaque Distance Distance Distance (mm) On Off A LED On LED Off B 0 331.48 125.26 206.22 242.74 80.30 162.44 0.5 356.15 129.00 227.15 268.80 83.15 185.65 1.0 355.63 129.53 226.10 285.68 81.84 203.84 1.5 345.75 126.58 219.17 291.42 80.96 210.46 2.0 337.68 128.27 209.41 295.05 82.95 212.10 2.5 327.62 127.24 200.38 295.38 81.05 214.33 3.0 316.36 127.87 188.49 287.32 81.91 205.41 3.5 300.70 122.00 178.70 278.04 77.11 200.93 4.0 296.38 127.90 168.48 275.14 81.41 193.73 4.5 277.42 120.84 156.58 260.42 76.53 183.89 5.0 273.38 128.21 145.17 257.83 81.04 176.79 5.5 220.13 83.10 137.03 223.33 54.00 169.33 6.0 258.05 128.67 129.38 242.81 82.48 160.33 6.5 249.26 127.68 121.58 233.68 81.00 152.68 7.0 241.89 128.50 113.39 225.61 82.33 143.28 7.5 236.22 129.06 107.16 219.78 81.61 138.17 8.0 230.22 129.44 100.78 212.61 81.56 131.05 8.5 225.94 129.59 96.35 208.47 82.24 126.23 9.0 216.50 128.35 88.15 200.35 81.40 118.95 9.5 214.35 129.00 85.35 195.95 81.80 114.15 10.0 212.87 131.33 81.54 194.47 82.93 111.53

The value of Column A (Total Plaque) was plotted against Column B (Total Distance). The resulting line was curve fitted to the follow straight line equation:

Total Plaque=1.304(Total Distance)−66.61  (III)

Since the value of Total Plaque at a distance of 1 mm from the surface of the model tooth surface was 226, a Compensated Plaque Value (CPV) was determined using:

CPV=226+(1.304(Total Distance)−66.61)/Total Plaque  (IV)

Table II shows the calculated CPV versus distance.

TABLE II CPV as a function of distance for oral cleaning device. Distance Total Plaque (mm) A 0 226.70 0.5 226.77 1.0 226.88 1.5 226.95 2.0 227.00 2.5 227.06 3.0 227.15 3.5 227.09 4.0 227.10 4.5 227.11 5.0 227.13 5.5 227.12 6.0 227.10 6.5 227.09 7.0 227.06 7.5 227.06 8.0 227.04 8.5 227.02 9.0 227.01 9.5 226.97 10.0 226.97 AVERAGE 227.02 Std. Dev. 0.12

The table shows the average calculated CPV independent of distance is 227.02, with a standard deviation of 0.012 (0.05%). So, the value of the plaque reading has been compensated for, taking into account the distance from the optical collector to the surface of the model tooth.

Example 2 Use of the Oral Cleaning Device

The device described in Example 1 was used in a study to clean human teeth. Participants in the study did not perform any oral hygiene for 18-24 hours before the study was performed. The study was conducted using surrogate brushing by a hygienist using the American Dental Association approved Bass Method. The mouth was divided into 12 equal sections so that each section could be analyzed individually. The maximum total time period for brushing of each section was predetermined and set to 10 seconds to simulate an entire mouth brushing time of two minutes. During brushing, the data produced with the device was output via serial communication to a PC that recorded the data.

FIG. 4 is a sample plot of the data produced from the device during the 10 second brushing of a particular section of the mouth. The data oscillates up and down because the detecting portion of the brush is repeatedly traveling over areas within the section containing different levels of plaque. A linear trend line drawn through the data shows the reduction of plaque during the 10 second time period.

While the foregoing description and drawings represent exemplary embodiments of the present invention, it will be understood that various additions, modifications and substitutions may be made therein without departing from the spirit and scope of the present invention. One skilled in the art will appreciate that the invention may be used with many modifications of structure, arrangement, proportions, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the principles of the present invention. For example, elements shown as integrally formed may be constructed of multiple parts, or elements shown as multiple parts may be integrally formed, the operation of elements may be reversed or otherwise varied, or the size or dimensions of the elements may be varied. Therefore, the presently disclosed embodiments are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and not limited to the foregoing description. 

1. A method for cleaning an oral cavity, said method comprising: a. positioning within said oral cavity a device suitable for detecting and removing plaque from a surface of at least one tooth of said oral cavity, said device comprising a source for emitting light, b. substantially simultaneously cleaning and irradiating said surface of at least one tooth in said oral cavity, said at least one tooth having applied thereto a fluorescent agent capable of binding to plaque on said at least one tooth, with said light of a wavelength effective to provide a fluorescent emission when contacted with said fluorescent agent on said at least one tooth, c. collecting at least a portion of said fluorescent emission over a predetermined first time period, d. determining an average plaque value (APV) based on said fluorescent emission collected over said predetermined first time period, e. comparing said APV to a predetermined plaque value (PPV), f. continuing to substantially simultaneously clean and irradiate said at least one tooth for a predetermined second time period.
 2. The method of claim 1 wherein reflected light resulting from contact of said incident radiation with said surface is collected essentially simultaneously with said fluorescent emission and said APV is a compensated APV.
 3. The method of claim 1 wherein said fluorescent agent comprises fluorescein or a salt thereof.
 4. The method of claim 3 wherein said incident radiation has a peak wavelength of from about 450 to about 500 nanometers.
 5. The method of claim 4 wherein said portion of said fluorescent emission has a peak wavelength of from about 520 to about 530 nanometers.
 6. The method of claim 1 wherein said predetermined first time period is from about 0.25 to about 10 seconds.
 7. The method of claim 1 wherein said predetermined second time period is from about 0.5 to about 45 seconds.
 8. The method of claim 1 wherein said predetermined maximum time period is from about 60 to about 180 seconds.
 9. The method of claim 5 wherein said portion of said reflected light is simultaneously conveyed with said portion of said fluorescent emission through an optical filter prior to conversion of said optical signal of said fluorescent emission to said electrical signal of said fluorescent emission, said filter removing light having a wavelength of above about 515 nanometers.
 10. The method of claim 2 wherein said compensated plaque value is determined as a function of the distance between said point of collection of said fluorescent emission and said surface of said oral cavity.
 11. The method of claim 1 further comprising determining a distance range of said light source from said surface over said predetermined second time period and comparing said distance range to a predetermined distance threshold.
 12. The method of claim 1 further comprising continuing to simultaneously clean and irradiate said surface of said oral cavity until all of a plurality of sections of said oral cavity have been cleaned, or for a predetermined maximum time period, whichever occurs first.
 13. The method of claim 1 wherein said cleaning is effected by sonification, pressurized water and brushing.
 14. The method of claim 13 wherein said brushing is effected by a power toothbrush or a manual toothbrush.
 15. The method of claim 12 wherein said cleaning is effected by sonification, pressurized water and brushing.
 16. The method of claim 15 wherein said brushing is effected by a power toothbrush or manual toothbrush. 